Present embodiments relate generally to the field of drilling and processing of wells. More particularly, present embodiments relate to continuous circulation systems and methods.
In conventional oil and gas operations, a drilling rig is used to drill a wellbore to a desired depth using a drill string, which includes drillpipe, drill collars and a bottom hole drilling assembly. During drilling, the drill string may be turned by a rotary table and kelly assembly or by a top drive to facilitate the act of drilling. As the drill string progresses down hole, additional drillpipe is added to the drill string.
During drilling of the well, the drilling rig may be used to insert joints or stands (e.g., multiple coupled joints) of drillpipe into the wellbore. Similarly, the drilling rig may be used to remove drillpipe from the wellbore. As an example, during insertion of drillpipe into the wellbore by a traditional operation, each drillpipe element (e.g., each joint or stand) is coupled to an attachment feature that is in turn lifted by a traveling block of the drilling rig such that the drillpipe element is positioned over the wellbore. An initial drillpipe element may be positioned in the wellbore and held in place by gripping devices near the rig floor, such as slips. Subsequent drillpipe elements may then be coupled to the existing drillpipe elements in the wellbore to continue formation of the drill string. Once attached, the drillpipe element and remaining drill string may be held in place by an elevator and released from the gripping devices (e.g., slips) such that the drill string can be lowered into the wellbore. Once the drill string is in place, the gripping devices can be reengaged to hold the drill string such that the elevator can be released and the process of attaching drillpipe elements can be started again. Similar procedures may be utilized for removing drillpipe from the wellbore.
Various fluids (e.g., drilling fluid or mud) may be utilized in well-related operations. For example, drilling fluid is typically circulated through the wellbore during rotary drilling operations. This circulation functions to bring cuttings to the surface, cool and lubricate aspects of the drill string (e.g., the drill bit), hold back subsurface pressure, and so forth. It is desirable to provide improved fluid circulation systems and methods for drilling-related applications.